Wrong TTID and TTFD

[ohjunki]

Integration

sentry-android

Build System

Gradle

AGP Version

8.1.0

Proguard

Enabled

Version

7.2.0

Steps to Reproduce

There is a case where TTID and TTFD are incorrectly recorded. The reproducible path is as follows: when Activity(1) is turned on, if you immediately enter the new Activity(2) within 1-2 seconds, and then return to Activity(1), TTID and TTFD are overwritten with onResume timestamp values, resulting in incorrect values being recorded. The suspected code location is as follows.

sentry-java/sentry-android-core/src/main/java/io/sentry/android/core/ActivityLifecycleIntegration.java

Line 564 in 9119d59

MeasurementValue.KEY_TIME_TO_FULL_DISPLAY, durationMillis, MILLISECOND);

However, it seems to be frequently reproducible when the time between starting Activity(1) and returning to Activity(1) is within about 3 seconds. If you navigate to Activity(2) and stay there for a while, you can confirm that TTID and TTFD of Activity(1) are correctly recorded on the Discovery page. However, in cases where you return within 3 seconds, there are occasional instances of incorrect recording.

Expected Result

Activity(2) was started through a button click in Activity(1), and since TTFD was reported before the start, it should represent the time just before Activity(2) started.

Actual Result

The time when returned to Activity(1).

┆Issue is synchronized with this Jira Improvement by Unito

[kahest]

Hey @ohjunki thanks for reporting and the detailed steps to reproduce! If you're using SaaS, would you be able to post links to transactions that show this behavior (vs. transactions that don't)? You can also send them to karl.struggl@sentry.io if you prefer.

[romtsn]

The solution would be to only set TTID/TTFD values once and not overwrite when coming back to onResume for already running transaction

[ohjunki]

Hi @kahest I sent the link via email, which subject is "[sentry-java][issue-3145] TTID TTFD debug content". Thank you for the prompt response!